The present invention relates to a laser sputtering apparatus for depositing a thin film on a substrate for a thin film device.
There has been known this kind of a sputtering apparatus as disclosed in S. Komura et al., Japanese Journal of Applied Physics, vol. 27, 1988, page L23, which construction is shown in FIG. 6.
In the apparatus, in a vacuum chamber 21 capable of holding a vacuum by a gas discharging system 29 for creating a vacuum, a target 22 and a substrate holder 23 are arranged opposite to each other. A substrate 24 is held on the holder 23. Reference numeral 25 denotes a Q-Switched, YAG laser for visible radiations. A laser beam 26 with the second order harmonics, which has a wavelength of 532 nm, is condensed by an optical system 27 to be emitted onto the target 22 through a vacuum sealing window 28 arranged at the chamber 21, thus depositing a thin film on the substrate 24 by sputtering of the material of the target 22.
According to the above-described apparatus, however, the thin film is deposited a slow speed, and the sputtering substance from the target 22 becomes attached to the window 28, and thus the sputtering substance prevents the laser beam 26 from being transmitted through the window 28.
Also there are problems in that oxides and impurities easily contaminate into the target 22, previously manufactured in another process. In a case where the target 22 is made of an alloy or a compound, a thin film of a specified composition of the compound is not certainly formed because all of the component element is not uniformly sputtered. In comparison, there has been proposed a sputtering apparatus in which plural kinds of targets are arranged in parallel and laser beams are radiated to the targets to sputter in correspondence with the composition of each compound. However, the composition differs in accordance with the position on the substrate.